Several different types of soft tissue are found in human joints. For example, a joint can include articular hyaline cartilage, intra-articular fibrocartilage, tendons and ligaments. Articular hyaline cartilage is found on the surfaces of the bones of the joint. Intra-articular cartilage is found between the joint surfaces. Tendons connect muscle to the bones of the joint, and ligaments connect articular extremities of the bones of the joint.
When the soft tissue of a joint is no longer healthy, there can be debilitating pain in the joint. Soft tissue health can be adversely affected by disease, aging, or trauma. The adverse effects of disease, aging and trauma can be, for example, in the form of a tear in the soft tissue, or in the form of a breakdown, thinning or delamination of the tissue.
One form of intra-articular cartilage that is frequently damaged or degenerated is the meniscus of the knee. The meniscus is frequently damaged in twisting injuries. It is also damaged with repetitive impact over time. Meniscus degeneration can also occur by aging; as a person ages, the meniscus can become soft in places, so that even common motions like squatting can cause meniscal tears.
Common surgical procedures for treating meniscal damage include tear repairs and menisectomies. A tear repair is most commonly performed when the tear is a clean longitudinal vertical lesion in the vascular red zone of the meniscus. The basic strategy is to stabilize the tear by limiting or eliminating radial separation of the faces of the tear when the meniscus is load bearing. Many devices and surgical procedures exist for repairing meniscal tears by approximating the faces of the meniscus at the tear. Examples of such devices and procedures are disclosed in the following U.S. Pat. Nos. 6,319,271; 6,306,159; 6,306,156; 6,293,961; 6,156,044; 6,152,935; 6,056,778; 5,993,475; 5,980,524; 5,702,462; 5,569,252; 5,374,268; 5,320,633; and 4,873,976.
Menisectomies involve the surgical removal of part of the meniscus. Such procedures have generally been performed in cases of radial tears, horizontal tears, vertical longitudinal tears outside the vascular zone, complex tears, or defibrillation. Although menisectomies provide immediate relief to the patient, in the long term the absence of part of the meniscus can cause cartilage wear on the condylar surface, eventually leading to arthritic conditions in the joint.
Such surgical procedures are commonly performed arthroscopically. In arthroscopy, small incisions are made at the affected joint to form portals for the insertion of instruments, including a small lens and lighting system (an arthroscope). The arthroscope is connected to a viewing device, such as a television monitor to allow the surgeon to see the interior of the joint. Other instruments are inserted through other portals to perform a variety of tasks. For example, the surgical instrument may include an implement for manipulating native tissue (for example, tissue grasping, tissue cutting, bone abrading).
Typical surgical instruments used in arthroscopic procedures include rongeurs, such as the Kerrison rongeur, punch forceps, basket forceps, suction punches and cup curet, for example. Examples of arthroscopic instruments are described and illustrated in O'Connor's Textbook of Arthroscopic Surgery, 2nd ed., 1992, Chapter 19.
Other common surgical techniques in orthopaedic surgery include open surgery and mini-arthrotomy. For example, for knee surgery, the surgery may be performed by an open knee arthrotomy, where the incision may typically be 20-30 cm in length, and wherein the patella is everted during surgery. Knee surgery may also be performed by a mini-knee arthrotomy, where the incision is typically 10-13 cm in length and patella tension is avoided.
Intra-articular fibrocartilage is also present, for example, in the temporomandibular joint and between vertebrae. Injury and degeneration can also occur to the intra-articular fibrocartilage in these other joints.
Another common site of soft tissue injury and degeneration is the rotator cuff in the shoulder. The rotator cuff comprises the tendons that attach muscles to a bone in the shoulder. Where one of the tendons is thin, delaminated or frayed to the point that surgical repair or reconstruction is necessary, the damaged tendon can be reinforced with graft tissue or with an orthopaedic implant.
A variety of orthopaedic implants are available for treating damaged soft tissue at a joint site. One commercially available orthopaedic implant is the RESTORE™ orthobiologic implant. The RESTORE™ orthobiologic implant comprises layers of small intestine submucosa. The commercial RESTORE™ product is typically sold in the form of a thin circular sheet with a diameter of about 2.5 inches in diameter. Other shapes and sizes of RESTORE™ orthobiologic implants can be used. In addition, the surgeon can cut the commercial RESTORE™ product intra-operatively to the desired shape and size. The RESTORE™ implant is used in treating rotator cuff injuries.
Orthopaedic implants for treatment of damaged menisci are disclosed in the following U.S. Pat. Nos. 6,042,610; 5,735,903; 5,681,353; 5,306,311; 5,108,438; 5,007,934; and 4,880,429.